UC3867N

The UC3867N is a resonant-mode Power Supply Controller IC optimized for the control of zero current switched and zero voltage switched quasi-resonant converters. The primary control blocks implemented include an error amplifier to compensate the overall system loop and to drive a voltage controlled oscillator (VCO), featuring programmable minimum and maximum frequencies. Triggered by the VCO, the one-shot generates pulses of a programmed maximum width, which can be modulated by the zero detection comparator. This circuit facilitates "true" zero current or voltage switching over various line, load and temperature changes and is also able to accommodate the resonant components' initial tolerances. Under-voltage lockout is incorporated to facilitate safe starts upon power-up.

• Controls zero current switched (ZCS) or zero voltage switched (ZVS) quasi-resonant converters
• Zero-crossing terminated one-shot timer
• Precision 1%, soft-started 5V reference
• Programmable restart delay following fault
• 150µA Typical low start-up current
• Dual 1A peak FET drivers
• Green product and no Sb/Br

Applications

Power Management